It sits about 3 metres inside the bank, unremarkable to the casual eye, yet that subsidence in the earth is likely all that remains visible of something that once ran beneath your feet.

The depression is thought to be evidence of collapsed souterrain chambers. A souterrain is an underground stone-lined passage or chamber, typically constructed during the early medieval period in Ireland, usually in association with a ringfort. Ringforts, circular enclosures defined by earthen banks and ditches, were the dominant settlement form of early medieval Ireland, and souterrains were commonly built within them, probably serving as cool storage for foodstuffs, as places of refuge, or both. The ringfort at Farahy, recorded as CO018-040, retains its bank, and this slight hollow near its inner edge suggests the roof of at least one underground chamber has long since given way, leaving the ground to settle into the shape of what lies below.